/* (C) 1999-2001 Paul `Rusty' Russell * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */#include <linux/types.h>#include <linux/sched.h>#include <linux/timer.h>#include <linux/netfilter.h>#include <linux/in.h>#include <linux/udp.h>#include <linux/netfilter_ipv4/ip_conntrack_protocol.h>unsigned long ip_ct_udp_timeout = 30*HZ;unsigned long ip_ct_udp_timeout_stream = 180*HZ;static int udp_pkt_to_tuple(const struct sk_buff *skb,			     unsigned int dataoff,			     struct ip_conntrack_tuple *tuple){	struct udphdr hdr;	/* Actually only need first 8 bytes. */	if (skb_copy_bits(skb, dataoff, &hdr, 8) != 0)		return 0;	tuple->src.u.udp.port = hdr.source;	tuple->dst.u.udp.port = hdr.dest;	return 1;}static int udp_invert_tuple(struct ip_conntrack_tuple *tuple,			    const struct ip_conntrack_tuple *orig){	tuple->src.u.udp.port = orig->dst.u.udp.port;	tuple->dst.u.udp.port = orig->src.u.udp.port;	return 1;}/* Print out the per-protocol part of the tuple. */static unsigned int udp_print_tuple(char *buffer,				    const struct ip_conntrack_tuple *tuple){	return sprintf(buffer, "sport=%hu dport=%hu ",		       ntohs(tuple->src.u.udp.port),		       ntohs(tuple->dst.u.udp.port));}/* Print out the private part of the conntrack. */static unsigned int udp_print_conntrack(char *buffer,					const struct ip_conntrack *conntrack){	return 0;}/* Returns verdict for packet, and may modify conntracktype */static int udp_packet(struct ip_conntrack *conntrack,		      const struct sk_buff *skb,		      enum ip_conntrack_info conntrackinfo){	/* If we've seen traffic both ways, this is some kind of UDP	   stream.  Extend timeout. */	if (test_bit(IPS_SEEN_REPLY_BIT, &conntrack->status)) {		ip_ct_refresh(conntrack, ip_ct_udp_timeout_stream);		/* Also, more likely to be important, and not a probe */		set_bit(IPS_ASSURED_BIT, &conntrack->status);	} else		ip_ct_refresh(conntrack, ip_ct_udp_timeout);	return NF_ACCEPT;}/* Called when a new connection for this protocol found. */static int udp_new(struct ip_conntrack *conntrack, const struct sk_buff *skb){	return 1;}struct ip_conntrack_protocol ip_conntrack_protocol_udp= { { NULL, NULL }, IPPROTO_UDP, "udp",    udp_pkt_to_tuple, udp_invert_tuple, udp_print_tuple, udp_print_conntrack,    udp_packet, udp_new, NULL, NULL, NULL };